A droplet jet device includes a droplet jet unit configured to jet droplets through plural nozzles. The droplet jet unit has a common liquid chamber and individual liquid chambers. The droplet jet unit guides liquid supplied to the common liquid chamber to each of the individual liquid chambers and then jets the liquid from the individual liquid chambers to the outside through the nozzles. Representative droplet jetting systems include: a system configured to mechanically deform each of the individual liquid chambers in order to produce a pressure therein, thereby jetting droplets; and a system configured to vaporize the liquid contained in each of the individual liquid chambers by means of a heating element disposed therein in order to produce a pressure therein, thereby jetting droplets.
In incorporating the droplet jet unit into the droplet jet device, conventionally, use has been often made of a flow path forming member and a base member. The flow path forming member serves to form a flow path through which liquid to be introduced into the droplet jet unit flows. The base member serves to carry thereon some parts including the droplet jet unit and the flow path forming member. Conventionally, the reliability of such a droplet jet device has been improved by making contrivances to the configurations of the droplet jet unit, flow path forming member and base member and to the manner of assembling these components.
In recent years, by an increase in the nozzle density or nozzle count of the droplet jet unit, the droplet jet device has come to generate heat easily. As a result, a problem has arisen that crack occurs during use due to differences in linear expansion coefficient among the materials forming respective of the droplet jet unit, flow path forming member and base member.
Conventional techniques for solving such a problem include a technique wherein an elastic member is disposed between the droplet jet unit and the base member (see patent document 1 for example), and a technique wherein a ceramic material is used for the base member (see patent document 2 for example). These techniques have been said to be capable of preventing the occurrence of crack or the like due to the difference in linear expansion coefficient between the droplet jet unit and the base member.
The droplet jet device further includes a driving circuit for driving the droplet jet unit. The driving circuit is connected to the droplet jet unit via a connecting section. Such driving circuit and connecting section are susceptible to liquid and, hence, it is sometimes the case that the driving circuit and connecting section are damaged when splashed with liquid. For this reason, some conventional droplet jet devices are each provided with a protection cover for protecting the driving circuit and connecting section (see patent document 3 for example).    Patent document 1: Japanese Patent Laid-Open Publication No. 2001-322285A    Patent document 2: Japanese Patent Laid-Open Publication No. 2000-190500A    Patent document 3: Japanese Patent Laid-Open Publication No. 2004-262203A